According to a recent study, as many as 77 percent of all Americans
may be deficient in the vitamin essential for bone health and
which may prevent H1N1 (Swine Flu) and seasonal flu, wheezing,
winter-related eczema, upper respiratory infections and may help
prevent cancer, autoimmune diseases such as multiple sclerosis,
Type 1 diabetes, certain infectious diseases, myocardial infarctions
 heart attacks  and many other serious diseases.

When subgroups of the population are considered, depending on
which of the many reasonable definitions of deficiency are accepted,
the picture is even more ominous. For example, an important new
study from Children's Hospital in Boston found that as many as
80 percent of Hispanic children and 92 percent of black children,
what the study calls non-Hispanic black children, may also be
deficient in this vitamin.

We're talking about vitamin D, also called the sunshine vitamin
and often considered the nutrient of the year, if not the decade.
Its power as a determinant of human health can be captured by
what happens when someone is D deficient. They are at risk for
what is called rickets in children and osteomalacia in adults.

In its most extreme form, the bones soften and almost melt, making
them so fragile that the simple act of walking up steps may cause
bones to fracture and slight movement may cause excruciating pain.
In its most severe form, a blood test for vitamin D may show zero.
Dr. Fred Kaplan, an eminent orthopedic surgeon at the Hospital
of the University of Pennsylvania, whose patient had zero D, said
this is rare even in Third World countries.

Why, in the land of plenty and, now, also in the land of over-consumption,
overweight and obesity, can there be an epidemic of a vitamin
D deficiency or any other nutrient? The reasons may not be fully
understood, but the picture is still clear: Over time, we have
obtained most of our vitamin D from the sun. When ultraviolet
B rays hit the skin they cause the formation of vitamin D. But,
in an age of sunscreens and well-placed fear of skin cancer, we
tend to either stay out of the sun or use a sunscreen to shield
us from its rays, including the ultraviolet B ray.

Even if you stayed in the sun all day in some locations, you
would not get enough vitamin D. For example, north of Philadelphia,
between November and March, the suns rays are not strong enough
to precipitate the formation of vitamin D. And, during early morning
and late afternoon, the suns rays are not strong enough
to generate vitamin D. Thats a big part of the picture,
as authorities find that exposure to the sun is the main determinant
of vitamin D in humans. This leads us to the next source of vitamin
D  our food. Some dairy products, such as milk, are fortified
with vitamin D, but we tend to avoid dairy products due to their
cholesterol and saturated fat content. Other sources are fatty
fish such as salmon, tuna, mackerel, and herring. Still other
sources are fortified cereal and other foods such as orange juice,
now, often fortified both with vitamin D and calcium. But, most
people dont eat enough of these foods to get enough vitamin
D. So, that leaves supplementation with multi-vitamins that include
D, combination calcium and vitamin D pills, or vitamin D stand-alones.

There may be another reason for the epidemic  the epidemic
of the overweight and obese, who cannot process vitamin D efficiently
and are, consequently, more likely to be vitamin D deficient.
One final reason for identifying the epidemic is better testing
methods for vitamin D. There is a simple blood test now used to
determine vitamin D status.

Still another reason for the D epidemic is the aging of the population,
as older people  even the middle-aged  are more likely
to have D deficiency.

There are other risk factors for a D deficiency, but they probably
dont play a big role in the growing number of people with
that deficiency. Consumer Reports catalogued the following risk
factors: Being dark-skinned, middle-aged, or overweight;
having a history of gastric-bypass surgery or a condition that
interferes with the ability to absorb nutrients from food, such
as celiac disease; having a history of kidney or liver disease,
multiple sclerosis, osteoporosis, or thyroid problems; taking
medications that reduce blood levels of vitamin D, such as cholestyralmine
(Questran and generic), colestripel (Colestid and generic), certain
anticonvulsants; or orlistat (Alli, Xenical) (Consumer Reports
on Health, Nov. 2009).

This epidemic of vitamin D deficiency recently came into focus
with the publication of an important study led by Dr. Jonathan
Mansbach at Childrens Hospital In Boston. The study appears
in the November issue of the journal Pediatrics. The study looked
at vitamin D levels of 5,000 children and, extrapolating to the
entire U.S. population of children, found that millions were receiving
what the study called suboptimal levels of D. As noted above,
depending on the definition of deficiency or suboptimal levels,
the study found 80 percent of Hispanics and 92 percent of black
children were at the suboptimal levels. Others have previously
documented widespread vitamin D deficiency in children. For example,
Dr. Babette Zemel, a vitamin D expert at Childrens Hospital
of Philadelphia (CHOP), who is Director of the Nutrition and Growth
Laboratory of that hospital and Associate Professor of Pediatrics
at Penns medical school, found that 55 percent of children
she studied were vitamin D deficient, in a study published in
2007.

The Mansbach study notes that were far from knowing everything
we should about how to bring children and adults up to optimal
levels, how to avoid any long-run adverse consequences and exactly
what level of vitamin D is optimal.

It does recommend, in view of its findings, that children take
vitamin D supplements because of the clear health benefits from
doing so. The study doesnt make specific recommendations,
but the American Academy of Pediatrics recommends that children
with inadequate sun exposure get a daily intake of at least 400
International Units of vitamin D  vitamin D3 is now recommended
as it is better absorbed than D2. The adult recommendations, according
to a report in The American Family Physician, as cataloged by
www.medscape.com, are as follows:

 In older adults, vitamin D supplementation of 700 to 800
IU per day is associated with a lower risk for falls ... and fractures.

 To prevent vitamin D deficiency, adults with inadequate
sun exposure should have a vitamin D intake of 400 to 600 IU per
day.

 Adults with vitamin D deficiency, except for those with
malabsorption syndromes, should receive maintenance dosages of
800 to 1,000 IU of vitamin D per day.

Dr. Zemel recommends that most adults take vitamin D supplementation
of between 1,000 and 2,000 IU of vitamin D, which seems to make
the most sense in view of the evidence that Ive reviewed.
Of course, you may want to run this issue past your doctor at
your next visit. She said there is some variability in the response
to vitamin D so, some may reach optimal levels with 1,000 IU,
while others may require more. In severe deficiency cases, more
aggressive supplementation may be called for, such as 500,000
IU by injection.

The Medscape report also notes that excessive amounts of vitamin
D can be toxic. It states, Because vitamin D is fat soluble
and can be stored in fat, there are concerns regarding toxicity
from excessive supplementation. Signs and symptoms of vitamin
D toxicity may include headache, metallic taste, nephrocalcinosis
or vascular calcinosis, pancreatitis, nausea, and vomiting.
There is a study indicating toxicity is reached at 10,000 I.U.
daily. Dr. Zemel told me vitamin D toxicity is extraordinarily
rare.

You can be sure there will be continuing and extensive studies
of vitamin D to answer many questions. Dr. Mansbach says, We
need to perform randomized controlled trials to understand if
vitamin D actually improves these wide-ranging health outcomes.
At present, however, there are a lot of studies demonstrating
associations between low levels of vitamin D and poor health.
Therefore, we believe many U.S. children would likely benefit
from more vitamin D.

Although evidence is not clear on how to prevent H1N1 flu, the
suggestions for prevention include taking vitamin D supplements,
especially in the winter. In a report in the Examiner.com, five
simple steps are recommended to prevent H1N1:

Dr. Zemel believes it is too early to make hard and fast conclusions
on the vitamin D/H1N1 connection. Dr. Charlene Compher, an expert
on diet and health at Penn, agrees it is too early to draw conclusions
on H1N1. But, Dr. Zemel and others note that vitamin D does strengthen
the immune response and, therefore, may be useful in preventing
H1N1.

Dr. James E. Dowd, a professor of medicine at Michigan State
University and Diane Stafford stated, in their book The Vitamin
D Cure, about the flu/vitamin D connection, More respiratory
infections during the winter are probably directly related to
lower vitamin D production. They note several factors contribute
to the winter infection scenario. In the winter, there arent
as much ultraviolet B rays, which inactivate many viruses. With
less ultraviolet B getting through, humans produce less vitamin
D of their own. Finally, vitamin D is important to mobilize the
immune system response to infections. As a result of all this,
respiratory infections start to rise in late September and peak
in February. So, Dr. Dowds final advice is to forget the
chicken soup with too many noodles, too much salt, and too little
chicken and take vitamin D instead. My final advice is to get
chicken soup that doesnt have too much salt, too many noodles,
and too little chicken and get someone who can make unsalted chicken
soup, with the noodles and chicken you want and, then, take your
vitamin D.

Dr. Bruce Kinosian, a geriatrician at Penn and an expert on diet
and health, did sound a cautionary note, that vitamins thought
to be a magical cure-all often turn out to have quite the opposite
effect. He cites a long list of such vitamins of the year, which
later fizzled. The most prominent case involved vitamin E, which,
in excessive doses, was found to cause lung cancer in a segment
of the population.

Perhaps the most fundamental preventive approach was recently
recommended by Dr. Sidney Wolfe of the Health Research Group.
He said take the most powerful and effective drug  a healthy
lifestyle. This is the same prescription written over 800 years
ago by the eminent Jewish physician and philosopher Maimonides,
who said most of us die as a result of our lifestyle. Sometimes
ancient wisdom is more powerful than modern technology.

I cant resist one more observation on Maimonides. He was
born In Cordoba, Spain in 1135. But Cordoba was soon taken over
by a Muslim sect that demanded all infidels convert to Islam.
So the family had to emigrate. He ended up in Cairo, where he
practiced medicine. Of course, I doubt, if he were alive today,
even the greatest physician of his time would not be allowed to
practice medicine there. Does this piece of history suggest, the
more things change, the more they stay the same, and does it also
after a sad commentary on the state of human progress?